1. Field of the Invention
The present invention relates to an apparatus for purge to prevent AMC & natural oxide and, more particularly, to an apparatus for purge to prevent AMC & natural oxide using a Front Opening Unified Pod (hereinafter referred to as an ‘FOUP’) for carrying the wafer when fabricating semiconductor devices.
2. Description of the Related Art
In general, semiconductor devices are fabricated by performing a deposition process, a polishing process, a photolithography process, an etch process, an ion implantation process, a cleaning process, a test process, and an annealing process on a wafer selectively and repeatedly. In order for the wafer to be fabricated into the semiconductor devices, the wafer is carried to a specific position in each process.
In the semiconductor fabrication process, a processed wafer is contained in a wafer container, such as an FOUP, and carried as an article of high precision so that the wafer is not contaminated or damaged by external contaminants or shock.
Air introduced into the wafer transfer apparatus as described above is filtered, but a closed FOUP includes air that has not been filtered. Air within the closed FOUP includes molecular contaminants, such as oxygen (O2), water (H2O), and ozone (O3).
Accordingly the oxygen-containing gas contaminants within the closed FOUP forms a natural oxide layer on the wafer by naturally oxidizing a surface of the wafer within the closed FOUP. This natural oxide layer becomes a factor in deteriorating semiconductor production of good quality according to circumstances. If humidity within the closed FOUP is 40%˜50%, there is a problem in that semiconductor quality is deteriorated because the natural oxide layer of the wafer is activated and thus process characteristics are changed.